This disclosure relates to processing simulcast data.
In some radio broadcasting protocols, data can be transmitted simultaneously (simulcast) with broadcast content. For example, Radio Data System (“RDS”) is a simulcast protocol that allows data to be transmitted simultaneously with content in FM (Frequency Modulation) broadcast. RDS operates by adding data to a baseband signal that is used to modulate a radio frequency carrier. In some implementations of RDS broadcasting, the baseband signal has a number of components. Normal modulated audio signal that includes a left plus right (L+R) component is transmitted from 0 to 15 kHz (relative to the baseband). A stereo difference signal (L−R) component is transmitted on a 38 kHz subcarrier. RDS information (e.g., data) is transmitted on a 57 kHz subcarrier. Data are modulated and transferred at 1187.5 bits per second. RDS data can include free-form text that, after demodulation, can be displayed on a display device.